A Beam-Steering Broadband Microstrip Antenna with High Isolation

In this paper, a 4.2-7.2 GHz (52.6%) beam-steering microstrip antenna was proposed. The proposed antenna consists of three tapered slots and feeds. The three radiation directions of the antenna on the plane are independent of each other, and the three feeds correspond to the three radiation structures. Symmetry isolation trenches are introduced to improve isolation between different ports. Radiation pattern simulation and measurement show horizontal beam steering at the sampled frequencies of 4.2, 5, 6, and 7.2 GHz. The results shows that the overlapped beam of the three ports in the E-plane and H-plane can cover more than 200 degrees and 60 degrees, respectively. Apart from the capability of beam-steering, high isolation (more than 28 dB) of the proposed antenna in the operating band is obtained.